Sunday, June 2, 2013

Artificial Creek

Jordan creek is corralled by stone masonry walls, placed to keep the river channel static. Exactly what streams don’t do, stay still. Stream channels meander across valleys over time. They shift and move and shift again, and the walls that keep Jordan Creek static were the first sign this was a highly altered, artificial river system. The walls sever the natural link between the stream and its floodplain.
Trout were abundant, probably because they were recently stocked as part of a put and take fishery. Fisheries managers put hatchery raised rainbow trout in streams and fishermen take them out, which is just as well since the trout probably wouldn’t survive on their own. Regardless, they are a west coast fish and are not native to the east. In fact a few studies show that when rainbows are released into a stream their introduction significantly changes the feeding ecology of the stream.
But that doesn’t matter now because I love watching rainbows, native or not. Besides they are feeding with small mouth bass, another non-native top predator. Smallies are from the Mississippi river drainage, were widely introduced, and have had significant negative effects on native fish. And like the rainbows they are cool to watch native or not.
Trout have sleek muscular bodies that are perfect for holding in strong currents found in cooler stream environments. Bass are stockier and are better at hunting in slower moving warmer waters. While they are both top predators, they hunt different waters so they usually don’t directly compete. I have never seen them hunting side by side and it is a thrill to watch two top predators, both most efficient in their own water, hunting side by side.
The river is forced into a thin sheet of water over a low head dam that looks like at one time also served as a wet crossing for vehicles since it is about 6 foot wide. A red eared slider laid on the bottom of the quiet part of the plunge pool below the dam and craned its neck toward the surface to watch me watch it. Red eared’s are native to the midwest and were common pet store turtles. This reptile could be a pet that gained its freedom when its keeper got tired of caring for it. Or it could be part of the introduced eastern Pennsylvania population that is now reproducing.
The creek above the dam is a different world, more lake than river where thick beds of Hydrilla and Eurasian water milfoil cover the monotonous bottom. These plants are also aquarium escapees. Smallmouth bass stay just barely in view, and a stocked trout rockets into the muddy distance.
Everything I saw today in Jordan Creek is artificial. Non-native biology placed in an artificially constructed hydrology at the expense of a native stream scape. That doesn’t mean this wasn’t a phenomenal snorkel. Getting to see trout and bass feed side by side, and watching a red eared slider as intrigued by me as I was by it, was absolutely incredible, and I list this urban stream experience right up there with some of the most pristine streams I have snorkeled.
There isn’t much real in Jordan Creek, except for the sense of awe, wonder and adventure it provides me as I explore it. That and hope. Witnessing how life finds a way in response to a completely artificial habitat alteration gives me as much hope as knowing that people like the folks at Wildlands Conservancy (www.wildlandspa.org) are working to restore it.